An exhaust treatment apparatus is mounted on such a work vehicle as a hydraulic excavator, a bulldozer, and a wheel loader. As the exhaust treatment apparatus, for example, a diesel particulate filter apparatus (DPF), a diesel oxidation catalyst apparatus (DOC), a selective catalytic reduction apparatus (SCR), and the like are available.
An exhaust treatment apparatus reduces a nitrogen oxide (NOx) contained in a gas exhausted from an engine (an exhaust gas), to a harmless gas through NOx reduction reaction. A work vehicle includes a reducing agent tank for storing a reducing agent for NOx reduction reaction, and the reducing agent stored in the reducing agent tank is injected into the exhaust gas.
When an outside temperature is low and when a reducing agent stored in a reducing agent tank is frozen, there is a possibility that the reducing agent cannot be supplied to the exhaust treatment apparatus.
Therefore, for prevention of freeze of a reducing agent stored in a reducing agent tank, PTD 1 proposes a scheme for preventing a reducing agent from freezing, by introducing an engine coolant into a reducing agent tank and exchanging heat between the engine coolant and the reducing agent.
Specifically, PTD 1 proposes a scheme for preventing a reducing agent from freezing by exchanging heat between a reducing agent and a coolant which flows through a path formed by branching a part of a circulation path for an engine coolant and introducing the path into a reducing agent tank.